Walkers, climbers, and other participants can benefit from walking sticks that have the feature of returning kinetic energy that is acquired as the walking stick compresses in contact with the ground. This retained energy has the benefit that the users have to expend less of their own energy moving their legs forward, thus allowing them to walk or climb further and faster more comfortably and with less fatigue. Experiencing this advantage, the user will increase their interest in the activity and become a more active person.
The use of a walking stick with an energy storage spring for returning energy to the walker is well known to those familiar with the art. An example is the use of energy storage springs in foot prosthesis; particularly those used for athletic purposes. Designs include that of U.S. Pat. No. 6,007,582 or that in use in the Flex-Foot®, manufactured by Ossur hf of Reykjavik, Iceland. Examples where a spring mechanism stores and then sequentially dissipates energy for the sole purpose of cushioning a walking stick are described in U.S. Pat. No. 6,131,592, U.S. Pat. No. 5,720,474, and FR2617023. These walking sticks utilize a mechanical device such as a coil spring or cylinder for a spring and do not make use of the compression of a flexure to return the energy from the material compressing as a step is taken.
A published paper entitled “The design of a compliant composite crutch” by D. Shortell et al. discloses two designs of crutches using composite materials. The first design utilizes a metal coil spring embedded in a single unit composite material crutch. The coil spring compresses under the weight of the user with a spring force in the range of 90 to 170 lbs. The spring force, which acts in the vertical direction, is for shock absorption, not as a forward propelling aid. A second crutch design utilizes the flexure of the S curve in the shaft of the crutch in place of the coil spring. The effective springs that are designed using the composite material in place of the coil spring also operate in the vertical direction for shock absorption, not as a forward propelling aid. Another feature of the crutches that are the subject of the Shortell et al. publication is a rigid armrest with a grip. These armrests are oriented in the vertical direction for the purpose of providing the user with more support.
Bio-mimicry is the study and emulation of nature and its processes and elements to draw inspiration in order to solve human problems. The term bio-mimicry takes roots from the Greek words bios, meaning life, and mimesis, meaning to imitate. Nature has many elegant solutions to adapt to difficult and diverse terrains and climates. For example, mountain goats have evolved feet that allow them to maintain sure-footing on steep, rocky slopes and powerful legs that give them the strength to climb these difficult slopes.
FIG. 1 depicts a walking stick currently available in the art. The walking sticks currently available have evolved from simple straight shafted walking canes and ski poles and do not look to nature for inspiration. The user holds the walking sticks using a “thumbs up” grip wherein the wrists are strained to a vertical position. This is a non-ergonomically sound position which increases strain on the wrists, hands, and forearms and also transfers less energy to the walking sticks themselves per unit of musculature effort. A user will necessarily have the arms extended into positions where their muscles can't transfer maximum leverage to the walking stick to assist with their forward motion. By holding the wrists and forearms in a more natural horizontal position, the user could proportionally output more power to the walking sticks to help propel them over the terrain they are traversing. The present invention takes its inspiration from nature and overcomes the ergonomic issues associated with the prior art.
Standard walking sticks, hiking poles, and ski poles can only assist a person's capability to negotiate a limited number of landscapes and ground conditions. There has been limited evolution of their tips, oftentimes referred to as “ferrules and baskets.” The ferrule and basket has been the standard up until now, with minimal design modification other than variations in materials, slight changes in shape, addition of hard points and shock absorbers. A walking stick that could readily accept an interchangeable shoe designed to improve traction on varying terrains would be a major improvement over the current art.
Another limitation of the standard walking stick is the pointed tip of the ferrule. This pointed tip cuts into the surface of the terrain the user is traversing. This contributes to deterioration of the terrain surface as the pointed tip slices through and grabs into the surface. It also causes the user to expend excess energy to remove the tip from the terrain surface and places transverse forces across the walking stick which contributes to walking stick failure (breakage). A walking stick that possessed a dual flexure spring configured in an S-shape would cause less damage to terrain as a user traversed the terrain and would not be susceptible to breaking the shaft due to normal wear.